Great Episode.
As a parent, I have to completely disagree with the choices Fiona made and I actually think she is somewhat selfish. She's taking care of those kids not out of love but out of fear of being alone and realizing that while she did what she had to do during Franks drug fueled episodes that she has worked well beneath her potential and has no more excuses for it.
She should have told Liam and Carl to stay with those gay parents. They were clearly well off and could have provided those two with a life she couldn't even come close to and they could have visited her pretty much at their leisure.
This would have given Lip no excuses to do dumb shyt to 'support' his fam and would have forced him to finish school and go to college, or at least reexamine his self destructive lifestyle.
The only kids that were in really bad situations were Debbie and Ian who isn't quite old enough to be on his own and the Black Chick and her boyfriend would have happily took those tho kids in, they're fairly low maintenance.
She has doomed those kids and herself. If I were Jimmy I would walk away, dude has thrown himself on the sword for a woman who at best is her 8 or 9th priority, he should have disappeared after she belittle his issues he had with has dad pickling sausages.